For years, devices for emitting fragrances into the air have been used to adjust the smell of a space. Some devices are configured to passively emit fragrances into the air, while others are designed to actively or forcefully emit fragrances into the air. Passive fragrance emitting devices rely only on stagnant or naturally-induced airflow to diffuse a fragrance into the air via unforced convection and/or radiation. In contrast, active fragrance emitting devices rely on artificially-induced airflow to diffuse a fragrance into the air primarily via forced convection. Many passive and/or active fragrance emitters known in the art require heat, a flame, wax, smoke, or some other catalyst in order to activate or effectively distribute fragrances, which results in certain distinct disadvantages and shortcomings.
Although artificially-induced airflow type devices offer advantages over passive airflow type devices, artificially-induced devices still suffer from several shortcomings. For example, known fragrance emitting devices that use a fan or other air moving device to induce an air flow often fail to provide an adequate degree of control over the strength of the fragrance being omitted. In other words, once activated, these fragrance emitting devices emit fragrance at a fixed volumetric flow rate and until the fragrance source is empty. Attempting to provide some control over the rate at which fragrance is emitted, some devices employ one or more adjustable vanes to adjust the size of the openings through which the fragrance is deployed into the air. However, the adjustable vanes merely affect the fluid flow dynamics after the fragrance is diffused into the air, such that the rate at which the fragrance is diffused remains the same.
Certain artificially-induced fragrance emitting devices also fail to adequately spread or diffuse the fragrance over a sufficiently large space. The flow coming out of such devices is often too concentrated to adequately diffuse throughout a given space.